Final answer:
The 10% salt solution is more concentrated than the 0.9% salt solution because it has a larger proportion of salt relative to the solvent, making option a) the 10% salt solution the correct answer.
Step-by-step explanation:
To answer the question: What is more concentrated: 10% salt solution or 0.9% salt solution? We must understand what concentration means. A concentrated solution has a relatively large amount of dissolved solute, while a dilute solution has a smaller amount. The percentages given here refer to the mass percentage of salt in the solution, which is a way to express the concentration quantitatively.
In this case, the 10% salt solution means that there are 10 grams of salt in every 100 milliliters (mL) of solution. On the other hand, a 0.9% solution has 0.9 grams of salt per 100 mL of solution. Therefore, option a) the 10% salt solution is more concentrated than option b) the 0.9% salt solution because it contains a greater proportion of salt relative to the amount of solvent (water).